If you like riddles and math, you might want to check out this thing in Harder (a building I have entered a grand total of three times) tomorrow night. Dr. Jennifer Taback of Bowdoin College will deliver a lecture titled “Secret Sharing Among Mathematicians.”

Here’s the Skid Prop:

Suppose you manage the Federal Reserve Bank of New York, and hold the combination to a safe containing millions, billions or perhaps even trillions of dollars (who really knows, after all!). You have n people working under you, and on any given day, k of them are at work. You cant trust any with the entire combination to the safe, but require that any set of k of these people are able to open the safe together. How can this be done? Mathematics comes to the rescue, and I will discuss two solutions to the Bank Teller Problem. One solution is classical, and very adaptable to other situations. The other is less so, but very, very clever.